Prodigy decided enough was enough and banned messages on its electronic network that criticized the charges. At the same time, the company kicked a "handful" of the dissenting subscribers off the service for taking their protest to advertisers on the network.

Protesting subscribers are angry because on Jan. 1 Prodigy intends to start charging for some of the messages members exchange over the computer network. That is the first exception to Prodigy's previous policy of furnishing all services for one flat fee -- $12.95 a month, or $9.95 a month for a yearly subscription.

"Remember our martyrs! Let's not let them suffer in vain," one Defense Committee message on the network began, referring to seven Defense Committee members whose memberships were canceled.

Prodigy executives say excessive use of electronic messaging is costing the company millions of dollars and prevents it from operating profitably. Despite the protests, they say that the decision to charge 25 cents for each message after the first 30 per month is "carved in stone" and that no further discussion is needed.

In recent weeks, Prodigy has deleted many messages about the controversy from its network and has refused to meet with the dissidents.

Geoffrey Moore, Prodigy's director of marketing programs and communication, said the company had no plans to "sit down with a pressure group. They're trying to destroy our system. They talked to our advertisers. You don't negotiate with a group like that."

Prodigy, owned by International Business Machines Co. and Sears Roebuck, claims that a large number of messages sent by a small number of members crowd other discussion off the network. Mr. Moore said that overuse of the message feature caused operating "costs to skyrocket. We made a business decision."

Chris Hagin of Atlanta said Prodigy told him it canceled his membership because he had complained to advertisers.

Prodigy spokesman Brian Ek said Wednesday that no subscriptions were canceled for "voicing disagreement" but that fewer than a dozen members were kicked off because they "repeatedly sent harassing messages." He said repeated complaints to an advertiser would be considered harassment.

Greg Bobbs of Atlanta, a regional coordinator for the protest movement, said he was especially unhappy because some handicapped people use the message network as a support group.

"That's why people feel so betrayed, why the issue is emotional," said Penny Hay of Los Angeles, another member of the protest. "I get passionate letters from the disabled who have been using the messages. These people have found a life on Prodigy, and now they've lost everything."

Mr. Moore said protesters inflate their numbers by counting as a member each subscriber who answered a message that, he said, asked, "Which would you rather have: messages for free, or pay 25 cents?"

Despite all the furor, he said, membership is increasing past 600,000, at a rate "ahead of projections. And people are buying more from Prodigy advertisers. We expect to have a million members by the end of the year."

Henry Heilbrunn, Prodigy's vice president of media, said that the company never intended to charge for messages but that the unexpected volume led it to reconsider. He said 30 free messages would take care of the needs of 90 percent of Prodigy's subscribers.

"Besides, we never intended to be a messaging service," he said. "That's just one feature."